Summary

Councilman Golan Trevize, historian Janov Pelorat and Bliss of the planet Gaia (all of whom we last met in Foundation's Edge) set out on a journey to find humanity's ancestral planet -- Earth. The purpose of the journey is to settle Trevize's doubt with his decision at the end of Foundation's Edge.

They finally make it to Earth which is highly radioactive, and not capable of supporting life. The ship is drawn to the moon by an external force. They land, and find R. Daneel Olivaw, who explains that he has been paternalistically manipulating humanity for many millennia. He caused the settlement of Alpha Centauri, the creation of Gaia, and the creation of Psychohistory.

Trevize confirms his decision, as the numerous narrow escapes have convinced him that the creation of Galaxia is the correct choice.

Possible Sequel

Daneel continues to explain that since the dawn of civilization, man has been divided. This was the reason for his causing the creation of Psychohistory and Gaia. The book ending tells us:

"In all human history, no other intelligence has impinged on us, to our knowledge. This need only continue a few more centuries, perhaps a little more than one ten thousandth of the time civilization has already existed, and we will be safe. After all," and here Trevize felt a sudden twinge of trouble, which he forced himself to disregard, "it is not as though we had the enemy already here among us."

And he did not look down to meet the brooding eyes of Fallom - hermaphroditic, transductive, different - as they rested unfathomably, on him.